language: en

Core Selection Methods for Multicast Routing

Kenneth L. Calvert Ellen W. Zegura Michael J. Donahoo
GIT-CC-95/15

Abstract Multicast routing is an important topic of both theoretical and practical interest. Some recently-proposed multicast routing algorithms involve the designation of one or more network nodes as the "center" of the routing tree for each multicast group address. The choice of this designated router (which we refer to as the "core") influences the shape of the multicast routing tree, and thus influences performance of the routing scheme. In this paper we investigate the relationship between the choice of core and three performance measures. Specifically, we compare various methods of selecting a core with respect to their effect on bandwidth, delay, and traffic concentration. We conclude that simple methods are adequate for widely distributed groups, but that the addition of group information can be leveraged to improve performance especially when the group is small or exhibits a high degree of locality. We also conclude that core choice has a significant impact on traffic concentration, in fact traffic concentration effects can be ameliorated by appropriate core choice policies.

Keywords: Multicast routing, Scalability, Network modeling
College of Computing Georgia Institute of Technology
Atlanta, Georgia 30332-0280